Electrical impulse segregation circuits



May 5, 1942.. egg- 5 2,281,934

ELECTRICAL IMPULSE SEGREGA'IION CIRCUITS Filed Aug. 9, 1952 5 Sheets-Sheecl ll; l

2 1 C: r v 1 C INVENTOR MAX 65/652 BY I AT IY'ORNEYS y 1942- M. GEIGER 2,281,934

ELECTRICAL IMPULSE SEGREGATION CIRCUITS Filed.,Aug. 9, 1952 5 Shee ts-Sheet 2 INVENi'OR MAXZ/GEK BY 7% WW AT I'ORNEYS May 5, 1942.

M. GEIGER ELECTRICAL IMPULSE SEGREGATION CIRCUITS Filed. Aug. 9, I958 5 Sheets-Sheet 3 I NV E NTO R MAX 6mm BY anM AT TORNEYS May 5, 1942. M. GEIGER 2,281,934

ELECTRICAL IMPULSE SEGREGATION CIRCUITS Filed Aug. 9, 1938 5 Sheets-Sheet 4 INVENTOR MAX GF/GER ATTORNEYS May 5, 1942.

M. GEIGER ELECTRICAL IMPULSE SEGREGATION CIRCUITS Filed- Aug. 9, 1938' 5 Sheets-Sheet 5 INVENTOR MAX GE/GEK ATTORNEYS Patented May 5, 1942 ELECTRICAL EVIPULSE SEGREGATION CIRCUITS Max Geiger, Berlin, Germany, assignor to Telefunken Gesellschaft fiir Drahtlose Telegraphic m. b. H., Berlin, Germany, a corporation of Germany Application August 9, 1938, Serial No. 223,810 In Germany July 21, 1937 3 Claims.

In the signalling arts, for instance, in television, there is a certain problem that arises quite frequently, namely, to separate the various impulses comprised in a mixture of impulses, and to then cause the separated impulses to control various devices. Such a mixture may consist of impulses of dissimilar length or duration or else of different series or sequences of impulses all of which are of the same length.

The solution of this problem as disclosed in this invention is to be effected by utilizing the fact that a generator, such as an oscillator, for instance, has a different current load in the presence of different types of impulses which hereinafter will be referred to as states of synchronization. According to and by virtue of the different loads thus occurring different devices are controlled.

My invention will best be understood by reference to the figures in which Fig. 1 shows one embodiment thereof,

Figs. 2 through 5 are explanatory curves, and

Fig. 6 is a further embodiment thereof.

Referring to Fig. 1, there is shown an embodiment of my apparatus. pulse generator is, for instance, of the multivibrator type comprising the tubes 2 and 3. Tube 2 shall be assumed to comprise in addition to the control grid a further grid at which synchronization from a tube I is produced. The said tube 2 may be a screen-grid tube. Tube I is controlled at its control grid from incoming impulses of any desired low intensity. The impulses are amplified in tube I and they serve to control the impulse generator while the latter, in

turn, controls various devices according to the various impulses fed thereto, say, deflection or scanning generators in television receiver apparatus.

Examining, then, the voltage wave being of impulse nature arising at the plate of tube 2, there ensue, basically, four different states of synchronization:

I. The generator is synchronized so that both the anterior as well as the posterior fronts of the impulses, by compulsory action, are subject to synchronization.

II. Only the anterior front or face.

III. Only the rear fronts are subject to a compulsory action.

IV. The generator is not synchronized.

In each of these four states, the mean current load of tube 2 will be different as demonstrated by the following considerations: Fed to the grid of tube I are the negative impulses represented Suppose that the imin Fig. 2a; they are one-half the length of period I T. Suppose that at time n such an impulse is coming in, the plate current of tube I declines, the plate potential grows, and at the screen grid of tube 2 appears the potential Us2 (Fig. 2b) which causes a growth of plate current through tube 2, While decreasing the plate potential and thus the grid potential Ug3 at the tube 3 (Fig. 2c) As a result the current in tube 3 diminishes, the plate potential grows and thus also the potential at the control grid of tube 2. In this connection, the time-constant governing the potential and its shape at this grid (condenser 4, resistance 5) shall be assumed to be so chosen that the rise of potential just mentioned raises the grid potential beyond the point and level of incipient current flow (dash line). Hence, a current will then flow in tube 2, potential UgZ stays stable, and the potential slowly is equalized in accordance with an exponential function. At time t2 the end of the impulse (potential Ugl) is reached. The screen grid potential Usz declines again; as a result the current in tube 2 becomes lower, the plate potential rises, and as a consequence also the potential at the grid of. tube 3 grows. Also in this case Ug3 is to be raised again above the point of incipient current flow by choosing a suitable value for the time-constant of condenser 6 and resistance 1. The starting of current flow in tube 3 results in a decrease of plate potential and of voltage UgZ. Potential Ug3 then stays stable, and Ugz decays gradually. When instant is is reached, the cycle before described is repeated.

The potential UgZ was influenced both at time n as well as at time t2. Hence, the plate potential UA2 of tube 2 (Fig. 2e) furnishes a negative impulse between t1 and t2 which is synchronized at both fronts or ends. During the time elapsing between 121 and 722 a current flows in tube 2, and since in this case the duration of the impulse comprises a half-period, the mean current of tube 2 is characterized and determined by factor 0.5.

II. Next the instance shall be examined in which only one front of the impulse is subject to a compulsory action. The assumption shall here be made that the time-constant 4, 5, occupies percent and time-constant 6, I percent of the period T. Suppose that tube I is impressed with the short negative impulse illustrated in Fig. 3a. From analogous considerations, the voltage waves at the screen grid of tube 2 are as shown in Fig. 3d, at the control grid of tube 3 as in Fig. 30, at the control grid of tube 2 as in Fig. 3d and at the plate of tube 2 as in Fig. 3e.

But the rear end of the original impulse Ugl at time V1 is here not able to raise the grid potential Ug3 above the point of incipient current flow, and Ug3 takes a course in accordance with its time-constant 6, 1. During this time, UgZ stays constant. If, then, Ug3 attains the point where current flow begins, a current will flow in tube 3, the plate potential declines, and potential U z experiences a push into the negative region. UgZ in accordance with its time-constant and an exponential curve tends towards the potential of incipient current flow; however, before this point is reached spontaneously, it is raised above the said point by an impulse at time ts. And then the process as just described is reiterated.

III. Suppose that now a very long negative impulse is brought to act upon the tube I, then an impulse results at the plate of tube 2 whose rear end is subject to compulsory action. (Figs. 4a to 4c.) pulse Ugl represents the instant when UgZ experiences a. drop to zero grid potential and when potential UgZ drops markedly into the. negative range. This is the rear end of the negative impulse arising at the plate of tube 2 has a length of 0.4 X 7.

IV. In non-synchronized state, the presence of tube I shall be disregarded or the same be assumed to have a uniform and unvaried load so that it exercises no influence upon the actions of the multivibrator. What then results are the voltage Waves shown in Figs. 5cz-e. A current is here flowing in the tube 2 for a length of time equal to of the period (which is now longer).

In other Words, for the four synchronizing states there result mean current loads which, in the present example, are determinable by the following factors:

State I 0.5 State II 0.7 State III 0.4 State IV 0.54 /1 Now, quite a number of chances may be imagined so as to co-ordinate different devices to the various states of load. In the present instance, a simple scheme is shown in Fig. 6. In. series with the plate resistance 8 of tube 2 in the direction towards the battery is another res'mtance 9, and from the common pole or junction of the resistances 8 and 9 a condenser it is brought to ground potential. be assumed to be very high compared with the period T. Then, in the course or" a period, only voltage variations of relatively low amplitude will occur at the condenser it]. These voltage waves U02 are represented in Figs. 2 3 and 4 for the various synchronizing states of the multivibrator. (The non-synchronized state. shall here be left out of consideration.) In parallel relation to the plate battery is connected a potentiometer I l. Now, the various devices to be controlled are connected to diiierent taps ofv the said voltage divider, the same being here schematically indicated at Kl, K2, and K3. For instance, if the voltage at the condenser ll] fluctuates around the mean voltage value which is equal to the tapof Kl of the potentiometer, then Kl must respond. In order to raise the reliability of action of this arrangement, a potential could be derived from the generator just operating which will block the other devices K2 and K3.

If in the case shown in Fig. 6 the time-constant 9, I10 is so chosen that it is of the same order of magnitude as the period of the action, it will be The rear end of the long negative imwhich here The time-constant 9, Iii shall seen that the amplitudes of the voltage variations at the condenser I0 will be comparatively large, and the control of a device may be produced at a time when U02 inside the period attains a certain maximum or minimum value U or U (Fig. 29).

It is to be emphasized that the method hereinbefore disclosed and adapted to impulse separation is not confined to a time-base generator of the multivibrator type.

What is claimed is:

1. A multi-vibrator for producing voltage variations to be segregated comprising a first thermionic vacuum tube having anode, cathode and at least one control electrode, a second thermionic vacuum tube having anode, cathode and at least one control electrode, time constant means coupling the anode-cathode circuit of said first tube-to the control grid of said second tube, time constant means coupling the anode-cathode circuit of said second tube to the control grid of said first tube, a common means for energizing the anode-cathode circuit to both of said tubes, a potentiometer connected substantially in parallel with said energizing means, a load member, means for connecting one terminal of said load member to said potentiometer, capacity means coupling the other terminal of said load means to the cathode of said first and second tubes, means for connecting said other terminal of the load means to a point in the anode-cathode circuit of one of said tubes, a third thermionic tube having anode, cathode and at least one control electrode, means for impressing said impulses to be segregated onto the control grid-cathode circuit of said third tube, and means for coupling the anode-cathode circuit of said third tube to a control electrode of one of the other tubes.

2. A multivibrator for producing voltage variations and utilizing said variations to trigger load apparatus comprising a first thermionic tube having anode, cathode, and at least one control electrode, a second thermionic tube having anode, cathode, and at least one control electrode, a time constant circuit coupling the anode-cathode circuit of said first tube to a control electrode of said second tube, a time constant circuit coupling the anode-cathode circuit of said second tube to a control electrode of said first tube, means for energizing the anode-cathode circuit of both of said tubes, impedance means connected substantially in parallel with said energizing means, a plurality of load means connected to points on said impedance member and impedance coupled to the cathodes of said tubes, said load means being selectively energized in accordance with the voltage variations at the particular points of the impedance means to which said load means are connected, means connecting the impedance coupling means to the anode-cathode circuit of one of said tubes, and means for afiecting current flow in one of said tubes, said latter means being connected in the control electrode-cathode path of the tube.

3. Apparatus in accordance with claim 2, wherein said means for coupling said load to the cathode of both of said tubes comprises a condenser member having one terminal thereof electrically connected to at least a portion of said load and the other terminal thereof electrically connected to both of said cathodes.

MAX GEIGER. 

